Sander



A. w. LAIRD April 8, 1947.

SANDER Filed July 24, 1943 NMIS Il ...llv-

Avfonw aentor LVM Gttomegs Patented Apr. 8, v1947 i SANDER Alton W. Laird, Adams, N. Y., assignor to The New York Air BrakeCompany, a corporation of New Jersey Application July 24, 1943, Serial No. 496,092

7 Claims.

This invention relates to means for controlling sanding of rails ahead of braked wheels. The idea of the invention is to provide a sensitive device which will sense the condition of the rail at least as early as the commencement of a brake application. If the condition of the rail is such that slippage of braked wheels is likely to occur, the control device will start sanding of the rails and thus minimize the tendency for wheel slipping to occur.

After a wheel has been locked by the brakes and has started to slide, no amount of sanding will cause the wheel to rotate. Under such conditions sanding will merelyincrease the depths of the ats worn on the wheels. Hence it is important that the control device be so sensitive that it will respond before wheel sliding starts, and preferably a safe interval before it could possibly occur.

Generally stated the invention contemplates two feeler wheels which run on a rail. One runs free and the other is braked whenever a brake application is made. If the braked feeler wheel lags appreciably with reference to the unbraked feeler wheel, a reaction will be set up between the two, which is caused to operate the sanding device. The reaction might take several forms, but a dynamo electric eiect is the simplest available and is used.

It is desirable that the feeler wheels be in advance of any load bearing wheels of the train so that they will sense the condition of the rail before any wheel has modiiied it. The feeler wheels could, however, be located behind ran unbraked wheel and still function.

'I'he retarding eiect developed on the braked one of the two feeler wheel components can desirably be a little more severe than the braking effect simultaneously developed on the load bearing wheels of the vehicles. cause incipient slipping of the braked feeler wheel under conditions which will nearly, but not quite, cause slipping of the vehicle wheels. It is not contemplated that the braked feeler wheel will slide on the rail, but rather that it will slip. Slowed rotation rather than complete stoppage is the condition contemplated. However, stoppage will cause sanding.

A practical embodiment of the invention is illustrated in the accompanying drawing in which Figure 1 is a vertical axial section of the feeler mechanism in contact with the rail;

Figure 2 is a View on a smaller scale, partly kin elevation and partly in diagram, and illusi,

The purpose is to ieeler wheel 22.

2 trating conventionally the various connections. In Figure 1, 5 represents a bracket which is intended to be mounted on a frame of a locomotive (not shown), preferably ahead of the pilot wheels of the locomotive and certainly ahead of any wheels which are braked or sanded. `Piv oted at on the bracket 5 is a housing I whose form is indicated in the drawing. This housing is urged to tilt in a counter-clockwise direction on the pivot 6 by a spring 8. The bolt 9 serves as an adjustable limit stop for such motion.

Mounted in annular ball bearings Il and I2 carried by the housing is a shaft I3. The outer races of the annular ball bearings II and I2 are confined respectively by the threaded cap I4 and by the dust excluding retaining ring I5. The latter is held in place by wedging screws, one of which appears at I6. The outer race of the bearing I2 is also sustained by a combined ller piece and dust eXcluder I1.

Keyed to the shaft I3, at its lefthand end, is the braked feeler wheel I8 which is shown as a simple disk. Mounted on the hub of the ieeler wheel IB is an armature winding I9 of any ap propriate type. The coacting eld winding 2i is mounted within the hub of the free running y The hub of this free running wheel is mounted on annular ball bearings 23 which are carried by a secondary housing 24. The secondary housing 24 is tiltable on horizontal trunnions 25 carried by the housing 1. One trunnion 25 is indicated in dotted lines in Figure 1 and is more clearly shown in Figure 2. The secondary housing 24 is urged to tilt counter-clockwise by a coil compresison spring 25 which reacts between the secondary housing and the manhousing 1.

The springs 3 and 26 are so chosen that the peripheries of the feeler wheels I8 and 22 bear on the head of the track rail 2l with forces which are at least approximately equal so that they will have approximately the same adhesion to the rail. Absolute equality is probably not attainable, and is not essential so long as the relative adhesions are approximately stable.

Keyed to the righthand end of the shaft I3 is a hub 28 yand splined on this hub is a braking element 3! which also carries certain slip ringshereinafter described.

The member 3l has at its right a shaft-like extension which is slidable through they inner race of an annular ball bearing 32 whose outer race is fixed in the housing l. The member 3lA is urged to the right relatively to hub 28 andshaft I3 by a coil compression spring 29 and'carries a braking flange 33 which may engage the annular disk 34 mounted against the shoulder formed on the housing '1. The disk 34 is formed of brake lining material similar to that used in automobile brakes.

When the member 3| is forced to the left relatively to shaft I3, compressing spring 29, the flange 33 frictionally engages the annular member 34 and tends to retard the rotation of the feeler wheel I8. It is forced to the left during a brake application on the locomotive by the stem 35 attached to piston 36. Stem 35 engages a thrust head 3l mounted upon an annular ball bearing fixed in a cavity on the right end of the member 3l.

The piston 36 works in a cylinder 38. The space to the left of the piston 36 is vented to atmosphere, but a spring 39 mounted in that space biases the piston 36 to the right. The space within the cylinder 38 to the right of the piston 36 is connected by pipe 4I with the pipe which supplies air under pressure to the brake cylinder 42.

Cylinder 42 typies any brake cylinder on the locomotive. From this construction it results that the retarding effect between the flange 33 and the disk 34 is proportional to the intensity of brake applications. Thus the braking action on the shaft I3 and the feeler wheel I8 occurs only during brake application and is a simple function of the intensity of the application.

Leads 43 and 44 connect the terminals of the armature winding I8 to two insulated slip rings 45 and 46. These slip rings are respectively engaged by brushes 4l and 48. From the brushes 4l and 48 leads 49 and 50 extend to the terminals of the winding 5I of a sensitive relay switch. The contactor 52 of this switch is normally in circuitbreaking position but is picked up when the winding 5I is excited. It then closes a circuit through any source of current such as the battery illustrated and the winding 63 of a magnet valve. When the winding 53 is excited, it forces the armature 54 downward and actuates the sand controlling valve mechanism in housing 55.

This valve mechanism comprises a normally closed air supply valve 56 which is biased to closed position by supply pressure and a coil compression spring 5l, and an exhaust valve 58 which is formed on the lower end of the armature 54. When the armature is forced downward, the exhaust valve 58 closes and the supply valve 51 is unseated. This causes air under pressure to ow from any source typified by the supply line 6I to the sand pipe 62, operating the Sanders, not shown.

Operation The feeler wheels I8 and 22 run continuously on the rail head 21. When a brake application is made on the locomotive the braking pressure developed in the cylinder 42 is also effective in the cylinder 38 at the right of piston 36. Consequently the piston 36 is urged to the left with a force proportional to the intensity of the braking application.

This causes the disk 33 to engage the braking surface 34 and develop a retarding force on the feeler wheel I8. If the feeler wheel slips on the rail head 2l, it will lag behind the unbraked feeler wheel 22. The relative rotation of the windings I 9 and 2l will, when sufficient, develop an electromotive force which will operate the sensitive relay switch to cause the magnet valve to operate the Sanders.

It is contemplated that sanders will be located ahead of the leading braked wheels or ahead of each of the braked wheels on the train. In the latter case the magnet valves 53 will be duplicated at intervals and connected in one control circuit so that there will be one magnet valve for each sander to be controlled. This permits the speed of electric control to be attained as to all sanders.

The armature winding and the field winding are intended to typify any device (preferably electrical) which will sense minor relative rotation between the two feeler wheels I8 and 22. All that is required is some motion-indicating device which senses the occurrence of relative rotary motion between these wheels.

I prefer, however, to use a generator which will generate an electromotive force which rises approximately in proportion to the speed of rotation, and then fix the pick up point of the relay to cause operation at the proper slip indication.

The magnet valve 53 and the sensitive relay 5I are typical of controls which can be used with an air operated sander. Most sanders are air operated. The invention is not dependent upon the use of sanders of this type, but could control any sander.

While it is preferred to operate directly upon the rail and upon the rail in advance of any vehicle wheel wherever this is possible, it is feasible to sense the condition of the rail at various points in advance of sanding, and it is even possible to derive an approximate indication of the condition of the rail by sensing the condition of the tread of an unbraked leading wheel. A braked wheel would present an entirely different condition from that of the rail because the brakes working on the tread affect the condition of the tread. Direct sensing of the rail condition is obviously preferable.

What is claimed is:

l. Means for sensing the degree of slipperiness of a traction surface, comprising in combination a pair of wheels each normally rolling freely on said surface in adhesive contact therewith, said wheels being so arranged as to trace distinct laterally offset paths on said surface, so that neither affects the condition of the portion of the surface engaged by the other; means operable to impose a retarding effect on the rotation of one of said wheels; and force developing means adapted to be rendered active by relative rotation of said wheels.

2. Vehicle carried means for sensing the slipperiness of the traction surface of a track rail on which the vehicle runs, Comprising in combination a pair of sensing wheels each normally rolling freely on the traction surface of the rail in advance of all vehicle wheels which drive or are braked, said sensing wheels being arranged to trace distinct paths on said traction surface; yielding means sustained by the vehicle and serving to hold the sensing wheels in adhesive contact with the traction surface of the rail; means operable to impose a retarding effect on the rotation of cne of said sensing wheels; and means for generating an electromotive force which is approximately proportional to the rate of Vrelative rotation of the sensing wheels.

3. The combination of a track rail having a tractive surface; an air brake cylinder; means for controlling sanders for said tractive surface; a pair of sensing wheels each normally rolling freely on the tractive surface of the rail, and arranged to trace distinct paths thereon at points unaffected by sanding or the action of wheels which drive or are braked; yielding means serving to hold said sensing wheels in adhesive contact with said tractive surface; pressure operated braking means subject to pressure in said brake cylinder and serving when under pressure to resist rotation of one of said sensing Wheels; and means rendered active by relative rotation of said sensing wheels to operate said sender controlling means.

4. The combination of a track rail having a tractive surface; an air brake cylinder; means for controlling sanders for said tractive surface;

a pair of sensing Wheels each normally rolling freely on the tractive surface of the rail, and arranged to trace distinct paths thereon at points unaffected by sanding or the action of wheels which drive or are braked; yielding means serving to hold said sensing wheels in adhesive contact with said tractive surface; pressure operated braking means subject to pressure in said brake cylinder and serving when under pressure to resist rotation of one of said sensing Wheels; and means responsive to retardation of said braked sensing wheel relatively to the other sensing wheel and effective while said braked wheel continues to rotate, to operate said sander controlling means.

5. The combination of a track rail having a tractive surface; an air brake cylinder; means for controlling sanders for said tractive surface; a pair of sensing wheels each normally rolling freely on the tractive surface of the rail, and arranged to trace distinct paths thereon at points unaffected by sanding or the action of Wheels which drive or are braked; yielding means serving to hold said sensing wheels in adhesive contact with said tractive surface; pressure operated braking means subject to pressure in said brake cylinder and serving when under pressure to resist rotation of one of said sensing Wheels; means operated by relative rotation of said sensing wheels and serving to develop an electromotive force which is approximately proportional to the rate of such relative rotation; and a relay controlling said sander controlling means and adapted to respond to said electromotive force when the same attains a value materially less than that characteristic of sliding of the braked sensing wheel.

6. Means adapted for mounting on a railroad vehicle, to control a rail sander according to the degree of slipperiness of the rail and the intensity of a brake application comprising two sensing Wheels which normally roll freely on an unsanded portion of the tractive surface of the rail and trace thereon distinct paths; yielding means for holding said sensing wheels in adhesive contact with the rail; means for applying proportional braking effects to the vehicle and to one of said sensing Wheels; and sander controlling means arranged to initiate sanding upon relative rotation of the sensing wheels.

7. Means adapted for mounting on a railroad vehicle, to control a rail sander according to the degree of slipperiness of the rail and the intensity of a brake application comprising two sensing wheels which normally roll freely on an unsanded portion of the tractive surface of the rail and trace thereon distinct paths; yielding means for holding said sensing wheels in adhesive contact with the rail; means for applying proportional braking efiects to the vehicle and to one of said sensing Wheels; and sander controlling means arranged to initiate sanding when the braked sensing wheel slows relatively to the other sensing wheel, and before said braked sensing wheel slides on the rail.

ALTON W. LAIRD.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 505,976 Field Oct. 3, 1893 596,527 Morse Jan. 4, 1898 739,386 Cady Sept. 22, 1903 2,232,752 Wilson Feb. 25, 1941 2,038,146 Cook et al Apr. 27, 1936 FOREIGN PATENTS Number Country Date 25,764 English 1906 315,517 English July 18, 1929 

